New study of Cervarix shows two doses are adequate against HPV types 16 and 18

A new study of Cervarix (papillomarvirus vaccine) from Glaxo Smith Kline, finds that to protect women from HPV types 16 and 18, which account for 70% of cervical cancer cases, two doses of the vaccine are as effective as the standard three doses over a four-year period. The study, reported in The Journal of the National Cancer Institute, uses data from a community-based Cervarix trial in Costa Rica. Women were randomly selected to receive either Cervarix or a Hepatitis A vaccine control. Researchers had intended to give all 7,466 subjects the full course of three vaccines. However, approximately 20% only completed two doses of HPV or control vaccine. Those who had two doses were found to have the same strong protection as the ones who received three, after four years of follow up. The researchers observe that a single dose might also provide a high level of protection. J Natl Cancer Inst (2011) doi:10.1093/jnci/djr319